Electrode for polishing hollow tube, and electrolytic polishing method using same

Abstract

A wing electrode is configured by disposing at least a wing in a circumferential direction at equal intervals, the wing having a specific width in an axial direction of the electrode shaft and a tip in a shape corresponding to an inner surface of the hollow tube. A housing tube is arranged concentrically to the electrode shaft and to house the wing electrode by winding the respective wings around the electrode shaft. A slit of the housing tube is arranged in the axial direction so as to correspond to each wing. A diameter adjustment unit is operable to expand and contract each wing in the radial direction by rotating the electrode shaft and the housing tube relatively after inserting each wing into the slit of the housing tube. As a matter of course, the electrolyte is filled in the hollow tube at any time before the electrolytic treatment.

The invention claimed is: 
     
       1. An electrode for polishing a hollow tube comprising:
 an electrode shaft; 
 a wing electrode configured by disposing a wing or plural wings at equal intervals in a circumferential direction, the wing having a specific width in an axial direction of the electrode shaft and a tip in a shape corresponding to an inner surface of the hollow tube; 
 a housing tube arranged concentrically to the electrode shaft and housing the wing electrode winding the wings around the electrode shaft; and 
 a diameter adjustment unit operable to expand and contract each wing in the radial direction by rotating the electrode shaft and the housing tube relatively after inserting each wing to a slit of the housing tube in the axial direction corresponding to the each wing. 
 
     
     
       2. The electrode for polishing the hollow tube according to  claim 1 , wherein
 the hollow tube has periodical bulge parts in the axial direction, 
 a shape of the wing electrode corresponds to the bulge part, and 
 the number of the wing electrodes corresponds to the number of the bulge parts. 
 
     
     
       3. The electrode for polishing the hollow tube according to  claim 1 , wherein the wing electrode is made of a metal mesh, and is imparted with the flexibility and the electric insulation by impregnating a front and back surfaces of the electrode except the tip with the synthetic resin. 
     
     
       4. An electropolishing method for a hollow tube comprising steps of:
 inserting the electrode for polishing the hollow tube according to  claim 1  into the hollow tube in a state that a wing electrode is housed in a housing tube; 
 expanding the wing from the housing tube till a distance between a tip of the wing and the inner circumference surface of the hollow tube becomes a suitable distance for the electropolishing by rotating the electrode shaft against the housing tube; and 
 applying voltage and current of the polarity corresponding to the polishing between the hollow tube and the wing electrode. 
 
     
     
       5. The electropolishing method for the hollow tube according to  claim 4 , further comprising steps of:
 housing each wing of the wing electrode in the housing tube by rotating the electrode shaft against the housing tube in the reverse direction after the polishing is finished; and 
 extracting the wing electrode from the hollow tube to be polished.